Computers & Structures
In order to be cost-effective, space structures must be extremely light-weight, and subsequently, very flexible structures, The power system for Space Station 'Freedom' is such a structure. Each array consists of a deployable truss mast and a split 'blanket' of photo-voltaic solar collectors. The solar arrays are deployed in orbit, and the blanket is stretched into position as the mast is extended. Geometric stiffness due to the preload make this an interesting non-linear problem. The space station will be subjected to various dynamic loads, during shuttle docking, solar tracking, attitude adjustment, etc. Accurate prediction of the natural frequencies and mode shapes of the space station components, including the solar arrays, is critical for determining the structural adequacy of the components, and for designing a dynamic controls system. This paper chronicles the process used in developing and verifying the finite element dynamic model of the photo-voltaic arrays. Various problems were identified in the investigation, such as grounding effects due to geometric stiffness, large displacement effects, and pseudo-stiffness (grounding) due to lack of required rigid body modes. Various analysis techniques, such as development of rigorous solutions using continuum mechanics, finite element solution sequence altering, equivalent systems using a curvature basis, Craig-Bampton superelement approach, and modal ordering schemes were utilized. This paper emphasizes the grounding problems associated with the geometric stiffness.
Bosela P. A., Shaker F. J. and Fertis D. G. (1992) Dynamic Analysis of Space-Related Linear and Nonlinear Structures. Computers & Structures, 44, 5, 1145-1148 DOI: 10.1016/0045-7949(92)90335-W
NOTICE: this is the author’s version of a work that was accepted for publication in Computers & Structures. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Computers & Structures, 44, 5, (08-17-1992); 10.1016/0045-7949(92)90335-W